将store绑定到gridpanel组合框列extjs

Question

我想使用Extjs 4和MVC架构动态地将存储绑定到我的gridpanel中的combobox，我在按钮的clic处理程序中执行了此操作：

var prodRelStore = this.getGetProdRelDataStore();   
var mygridprodrel = scopegrid.getView().getHeaderCt().getHeaderAtIndex(2);//the combo column
    prodRelStore.getProxy().url = 'getprodrel.php';
    prodRelStore.autoSync = true;
    prodRelStore.load({
    params: {
            scope_name: scopename
            },
            scope : this
    });
    mygridprodrel.bindStore(prodRelStore);
    scopegrid.getView().refresh();

但我明白了：Uncaught TypeError: Object [object Object] has no method 'bindStore' 将商店动态绑定到gridpanel内的组合框的正确方法是什么？